<PAGE>

EXHIBIT 10.5.1

BIO-REFERENCE LABORATORIES, INC. 2000 EMPLOYEE INCENTIVE STOCK OPTION PLAN


1. PURPOSE. The purpose of the 2000 Employee Incentive Stock Option Plan (the
"Plan") is to advance the interests of BIO- REFERENCE LABORATORIES, INC. , a New
Jersey corporation (the "Company"), by strengthening the Company's ability to
attract and retain in its employ people of experience and ability, and to
furnish additional incentives to Employees (as such term is hereinafter defined)
of the Company and its subsidiaries upon whose judgment, initiative and efforts
the successful conduct and development of its business largely depends, by
encouraging them to become owners of the common stock of the Company.

Accordingly, the Company may, from time to time, grant to such Employees as may
be selected in the manner hereinafter provided, options to purchase the shares
of the Company's common stock, $.01 par value (the "Common Stock") upon the
terms and conditions hereinafter established. The options to be granted shall be
options which will qualify for incentive stock option treatment under the
Internal Revenue Code of 1986, as amended ("ISO's").

2. AMOUNT AND SOURCE OF STOCK. The aggregate number and class of shares which
may be the subject of options granted pursuant to the Plan is 800,000 shares of
Common Stock, $.01 par value, of the Company (the "Shares"), subject to
adjustment as provided in Paragraph 10. Such Shares may be reserved or made
available from the Company's authorized and unissued Shares or from Shares
reacquired and held in the Company's treasury. In the event that any option
granted hereunder shall terminate prior to its exercise in full, for any reason,
including, without limitation, an option exchange pursuant to Paragraph 12
hereof, then any remaining Shares not purchased pursuant to such option shall be
added to the Shares otherwise available for issuance pursuant to the exercise of
options under the Plan.

3. ADMINISTRATION OF THE PLAN. The Plan shall be administered by the Board of
Directors of the Company (the "Board"), or if so designated, by resolution of
the Board, by a committee selected by the Board (the "Committee"), and to be
composed of not less than two (2) members to be appointed from time to time by
such Board, and who, at any time they exercise discretion in administering the
Plan and within one year prior thereto, shall have not been eligible for
selection as a person to whom stock could have been allocated or to whom stock
options or stock appreciation rights could have been granted pursuant to the
Plan or any other plan of the Company or any of its affiliates entitling the
participants therein to acquire stock, stock options or stock appreciation
rights of the Company or any of its affiliates.

The Board or, if so designated, the Committee, shall have full authority to
interpret the Plan, to establish and amend rules and regulations relating to it,
to determine the Employees to whom options may be granted under the Plan, to
determine the terms and provisions of the option agreements and to make all
other determinations necessary or advisable for the administration of the Plan.
The Board or, if so designated. the Committee, shall have full authority to
amend the Plan; provided, however, that any amendment that (i) increases the
number of Shares that may be the subject of stock options granted under the
Plan, (ii) increases the period during which options may be granted or the
permissible term of options under the Plan, or (iii) decreases the minimum
exercise price of such options, shall only be adopted by the Board or, if so
designated, the Committee, subject to shareholder approval. No amendment to the
Plan shall, without the consent of the holder of an existing option, materially
and adversely affect his rights under any option. The date of which the Board
or, if so designated, the Committee adopts resolutions granting an option to a
specified individual shall constitute the date of grant of such option (the
"Date of Grant"); provided, however, that if the grant of an option is made
subject to the occurrence of a subsequent event (such as, for example, the
commencement of employment), the date on which such subsequent event occurs
shall be the Date of Grant. The adoption of any such resolution by the majority
of the members of the Board or, if so designated, the Committee, shall complete
the necessary corporate action constituting the grant of said option and an
offer of Shares for sale to said individual under the Plan.

4. (a) ELIGIBILITY. Employees of the Company or subsidiaries of the Company, as
determined by the Board or, if so designated, the Committee, shall be eligible
to receive options hereunder; provided, however, that no option shall be
granted hereunder to any person who, together with his spouse, children and
trusts and custodial accounts for their


                                        1

<PAGE>

benefit, immediately at the time of the grant of such option and assuming its
immediate exercise, would beneficially own, within the meaning of Section 424(d)
of the Internal Revenue Code of 1986, as amended (the "Code"), Shares possessing
more than ten percent (10%) of the total combined voting power of all of the
outstanding stock of the Company (a "Ten Percent Shareholder"), unless such an
option granted to the Ten Percent Shareholder satisfies the additional
conditions for options, designated as an ISO, granted to Ten Percent
Shareholders set forth in subparagraph (c)(5) of Section 422 of the Code. For
purposes of the Plan, an "Employee" shall include full and part time employees
of the Company or any subsidiary of the Company who may also be officers and/or
directors of the Company and/or any subsidiary; provided, however, that such
options shall only be issued to employees eligible to receive such options as
ISOs under the Code. Furthermore, for purposes of the Plan, a subsidiary shall
mean any corporation of which the Company owns or controls, directly or
indirectly, fifty percent (50%) or more of the outstanding shares of capital
stock normally entitled to vote for the election of directors and any
partnership of which the Company or a corporate subsidiary is a general partner.
From time to time the Board or, if so designated, the Committee shall, in its
sole discretion, within the applicable limits of the Plan, select from among the
eligible individuals those persons to whom options shall be granted under the
Plan, the number of Shares subject to each option, and the exercise price, terms
and conditions of any options to be granted hereunder .

(b) Notwithstanding anything to the contrary herein, the Board, or if so
designated, the Committee, shall only grant an option designated as an ISO to
such persons who are eligible to receive an ISO pursuant to Section 422 of the
Code.

5. (a) OPTION PRICE; MAXIMUM GRANT. The exercise price for the Shares
purchasable under options granted pursuant to the Plan shall not be less than
100%, or, in the case of an option granted to a Ten Percent Shareholder, 110% ,
of the fair market value per share of the Shares subject to option under the
Plan at the Date of Grant, as determined by the Board or, if so designated, the
Committee, in good faith. The Board, or if so designated, the Committee, shall
consider the closing price of the Common Stock on the date the option is granted
(if listed on a national securities exchange), the representative closing bid
price as reported by NASDAQ or the National Quotation Bureau, Inc. or such other
reasonable method based on market quotations. The exercise price for options
granted pursuant to the Plan shall be subject to adjustment as provided in
Paragraph 10.

(b) With respect to those options granted pursuant to the Plan, the aggregate
fair market value, determined as of the Date of Grant, of the Shares subject to
such options which may be granted to an individual and which are initially
exercisable in anyone calendar year , under this Plan and all other stock option
plans of the Company and of any parent or subsidiary of the Company pursuant to
which incentive stock options may be granted, shall not exceed $100,000. The
Board, or Committee, may adopt a vesting schedule as it may determine in
connection with any option granted under the Plan; provided, however, in no
event shall an option granted pursuant to the Plan vest more than $100,000 in
anyone year, determined at the time of grant.

6. (a) TERM OF OPTION. Subject to the provisions of the Plan, the Board, or if
so designated, the Committee, shall have absolute discretion in determining the
period during which, the rate at which, and the terms and conditions upon which
any option granted hereunder may be exercised, and whether any option
exercisable in installments is to be exercisable on a cumulative or
non-cumulative basis; provided, however, that no option granted hereunder shall
be exercisable for a period exceeding ten (10) years or, in the case of an
option granted to a Ten Percent Shareholder, five (5) years from the Date of
Grant. Unless the resolution granting an option provides otherwise, each option
granted hereunder shall, subject to the provisions of Paragraph 9 hereof, be
exercisable for a period of ten (10) years or, in the case of an option granted
to a Ten Percent Shareholder, five (5) years from the Date of Grant.

(b) The grant of options by the Board or, if so designated, the Committee, shall
be effective as of the date on which the Board or, if so designated, the
Committee, shall authorize the option; provided, however, that no option granted
hereunder shall be exercisable unless and until the holder shall enter into an
individual option agreement with the Company which shall set forth the terms and
conditions of such option. Each such agreement shall expressly incorporate


                                        2

<PAGE>

by reference the provisions of this Plan and shall state that in the event of
any inconsistency between the provisions hereof and the provisions of such
agreement, the provisions of this Plan shall govern.

7. EXERCISE OF OPTIONS. An option shall be exercised when written notice of such
exercise, signed by the person entitled to exercise the option, has been
delivered or transmitted by registered or certified mail to the Secretary of the
Company at its then principal office. Said notice shall specify the number of
Shares for which the option is being exercised and shall be accompanied by
(i) such documentation, if any, as may be required by the Company as provided in
subparagraph II(b), and (ii) payment in full of the aggregate option price. Such
payment shall be in the form of (i) cash or (ii) a certified check (unless such
certification is waived by the Company) payable to the order of the Company in
the amount of the aggregate option price. Delivery of said notice shall
constitute an irrevocable election to purchase the Shares specified in said
notice, and the date on which the Company receives the last of said notice,
documentation and the aggregate option exercise price for all of the Shares
covered by the notice shall be the date as of which the Shares so purchased
shall be deemed to have been issued. The person entitled to exercise the option
shall not have the right or status as a holder of the Shares to which such
exercise relates prior to receipt by the Company of the payment, notice and
documentation expressly referred to in this Paragraph 7.

8. EXERCISE AND CANCELLATION OF OPTIONS UPON TERMINATION OF EMPLOYMENT OR DEATH.
Except as set forth below, if a bolder shall voluntarily or involuntarily
terminate his service as an Employee of the Company or any subsidiary of the
Company, the option of such bolder shall terminate upon the date of such
termination of employment regardless of the expiration date specified in such
option. If the termination of employment is due to retirement (as defined by the
Board or, if so designated, the Committee, in its sole discretion), the holder
shall have the privilege of exercising any option which the holder could have
exercised on the day upon which he ceased to be an employee of the Company or
any subsidiary of the Company; provided, however, that such exercise must be
accomplished within the term of such option and within three (3) months of the
holder's retirement. If the termination of employment is due to disability (to
an extent and in a manner as shall be determined by the Board or, if so
designated, the Committee, in its sole discretion), he (or his duly appointed
guardian or conservator) shall have the privilege of exercising any option that
be could have exercised on the day upon which he ceased to be an employee of the
Company or any subsidiary of the Company; provided, however, that such exercise
must be accomplished within the term of such option and within one (I) year of
the termination of his employment with the Company or any subsidiary of the
Company. If termination of employment is due to the death of the holder, the
duly appointed executor or administrator of his estate shall have the privilege
at any time of exercising any option that the holder could have exercised on the
date of his death; provided, however, that such exercise must be accomplished
within the term of such option and within one (I) year of the holder's death.
For all purposes of the Plan, an approved leave of absence as defined under the
Code or Regulations thereunder for an ISO shall not constitute interruption or
termination of employment.

Nothing contained herein or in any option agreement shall be construed to confer
on any option holder any right to be continued in the employ of the Company or
any subsidiary of the Company or derogate from any right of the Company or any
subsidiary of the Company to retire, request the resignation of or discharge
such option holder, or to layoff or require a leave of absence of such option
holder (with or without pay), at any time, with or without cause.

9. NON-TRANSFERABILITY OF OPTIONS. No option granted under the Plan shall be
sold, pledged, assigned or transferred in any manner except to the extent that
options may be exercised by an executor or administrator as provided in
Paragraph 8 hereof. An option may be exercised, during the lifetime of the
holder thereof, only by such holder or his duly appointed guardian or
conservator in the event of his disability.

10. (a) ADJUSTMENTS UPON CHANGES IN CAPITALIZATION. If the outstanding Shares
are subdivided, consolidated, increased, decreased, changed into, or exchanged
for a different number or kind of shares or other securities of the Company
through reorganization, merger, recapitalization, reclassification, capital
adjustment or otherwise, or if the Company shall issue additional Shares as a
dividend or pursuant to a stock split, then the number and kind of Shares
available for issuance pursuant to the exercise of options to be granted under
this Plan and all Shares subject to the unexercised portion of any option
theretofore granted and the option price of such options shall be adjusted to
prevent the inequitable

                                        3
<PAGE>

enlargement or dilution of any rights hereunder; provided, however, that any
such adjustment in outstanding options under the Plan shall be made without
change in the aggregate exercise price applicable to the unexercised portion of
any such outstanding option. Distributions to the Company's shareholders
consisting of property other than shares of Common Stock of the Company or its
successors and distributions to shareholders of rights to subscribe for Common
Stock shall not result in the adjustment of the Shares purchasable under
outstanding options or the exercise price of outstanding options. Adjustments
under this paragraph shall be made by the Board or, if so designated, by the
Committee, whose determination thereof shall be conclusive and binding. Any
fractional Share resulting from adjustments pursuant to this paragraph shall be
eliminated from any then outstanding option. Nothing contained herein or in any
option agreement shall be construed to affect in any way the right or power of
the Company to make or become a party to any adjustments, reclassifications,
reorganizations or changes in its capital or business structure or to merge,
consolidate, dissolve, liquidate or otherwise transfer all or any part of its
business or assets.

(b) If, in the event of a merger or consolidation, the Company is not the
surviving corporation, and in the event that the agreement governing such merger
or consolidation do not provide for the substitution of new options or other
rights in lieu of the options granted hereunder or for the express assumption of
such outstanding options by the surviving corporation, or in the event of the
dissolution or liquidation of the Company, the holder of any option theretofore
granted under this Plan shall have the right not less than five (5) days prior
to the record date for the determination of shareholders entitled to participate
in such merger, consolidation, dissolution or liquidation, to exercise his
option, in whole or in part, without regard to any installment provisions that
may have been made part of the terms and conditions of such option; provided,
that any conditions precedent to such exercise set forth in any option agreement
granted under this Plan, other than the passage of time, have been satisfied. In
any such event, the Company will mail or cause to be mailed to each holder of an
option hereunder a notice specifying the date that is to be fixed as of which
all holders of record of the Shares shall be entitled to exchange their Shares
for securities, cash or other property issuable or deliverable pursuant to such
merger , consolidation, dissolution or liquidation. Such notice shall be mailed
at least ten (10) days prior to the date therein specified. In the event any
then outstanding option is not exercised in its entirety on or prior to the date
specified therein, all remaining outstanding options granted hereunder and any
and all rights thereunder shall terminate as of said date.

II. (a) GENERAL RESTRICTIONS. No option granted hereunder shall be exercisable
if the Company shall, at any time and in its sole discretion, determine that (i)
the listing upon any securities exchange, registration or qualification under
any state or federal law of any Shares otherwise deliverable upon such exercise,
or (ii) consent or approval of any regulatory body or the satisfaction of
withholding tax or other withholding liabilities, is necessary or appropriate in
connection with such exercise prior thereto. In any such events, the
exercisability of such options shall be suspended and shall not be effective
unless and until the grantee of such option has paid such withholding tax or
listing, registration, qualification or approval shall have been effected or
obtained free of any conditions not acceptable to the Company in its sole
discretion, notwithstanding any termination of any option or any portion of any
option during the period when exercisability has been suspended.

(b) The Board or, if so designated, the Committee, may require, as a condition
to the right to exercise an option, that the Company receive from the option
holder, at the time of any such exercise, representations, warranties and
agreements to the effect that the Shares are being purchased by the holder only
for investment and without any present intention to sell or otherwise distribute
such Shares and that the option holder will not dispose of such Shares in
transactions which, in the opinion of counsel to the Company, would violate the
registration provisions of the Securities Act of 1933, as then amended, and the
rules and regulations thereunder. The certificates issued to evidence such
Shares shall bear appropriate legends summarizing such restrictions on the
disposition thereof.

12. EXCHANGE OF OPTIONS. The Board, or if so designated, the Committee, shall
have the right to grant options hereunder that are granted subject to the
condition that the grantee shall agree with the Company to terminate all or a
portion of another option or options previously granted under the Plan. The
Shares that had been issuable pursuant to the exercise

                                        4

<PAGE>

of the option terminated in the exchange of options shall, upon such
termination, again become available for issuance pursuant to the exercise of
options under the Plan.

13. LOANS TO EMPLOYEES. The Board, or if so designated, the Committee, acting on
behalf of the Company, shall have the authority and may, in its sole discretion,
lend money to, or guaranty any obligation of, an Employee for the purpose of
enabling such Employee to exercise an option granted hereunder; the amount of
such loan or obligation, however, shall be limited to an amount equal to fifty
percent (50% ) of the exercise price of such option. Any loan made hereunder
shall bear interest at the rate of not less than the Base Rate of Chase
Manhattan Bank, N.A. at the time of such loan plus one percent (1%) per annum;
may be unsecured or secured in such manner as the Board, or the Committee, shall
determine, including, without limitation, a pledge of the subject shares; and
shall be subject to such other terms and conditions as the Board, or the
Committee, may determine.
14. TERMINATION. Unless the Plan shall theretofore have been terminated as
hereinafter provided, the Plan shall terminate on August 24, 2010, which date is
ten (10) years from the date of the original adoption hereof by the Board, and
no options under the Plan shall thereafter be granted, provided, however, the
Board at any time may, in its sole discretion, terminate the Plan prior to the
foregoing date. No termination of the Plan shall, without the consent of the
holder of an existing option, materially and adversely affect his rights under
such option.

The Plan shall be submitted to the shareholders of the Company for approval in
accordance with the applicable provisions of the New Jersey Business Corporation
Act as promptly as practicable and in any event within one year after the date
of the original adoption hereof by the Board. Any options granted hereunder
prior to such shareholder approval shall not be exercisable unless and until
such approval is obtained. If such approval is not obtained on or before August
24, 2001, which date is one ( 1) year from the date of the original adoption
hereof by the Board, the Plan and any options granted hereunder shall be
terminated.


                                       5